The present invention is directed to a reader apparatus of the type which projects a magnified image of a film frame onto the rear side of a viewing screen to facilitate forward viewing of the magnified image. The invention is more particularly directed to an improved ultrafiche reader which includes a carriage assembly for positioning a desired one of the film frames between the light system and projection system to facilitate viewing of the desired film frame.
Ultrafiche readers are well known in the art. Such devices generally comprise a light system and a projection system for magnifying and projecting one of the ultrafiche film frames onto a viewing screen. Inasmuch as there are a plurality of such film frames on a typical ultrafiche, they are extremely small, thus requiring a high order of magnification. As a result, only slight movement of the ultrafiche located between the light system and projection system causes a number of film frames to traverse across the optical axis of the projection system making the positioning of a desired film frame within the projection system optical axis difficult. It is therefore desirable to provide mechanical assistance to an operator so that a desired film frame of a known location on an ultrafiche may be more readily positioned within the optical axis of the projection system.
It is therefore a general object of the present invention to provide an improved ultrafiche reader apparatus.
It is another object of the present invention to provide an improved ultrafiche reader apparatus which includes an ultrafiche carriage assembly which affords a mechanical advantage to an operator so that a desired film frame may be selected for viewing.
It is a still further object of the present invention to provide an ultrafiche reader which has an ultrafiche carriage assembly affording vernier control of the position of the film frames of an ultrafiche to thereby reduce the criticality of operator manipulation while a particular film frame of known location on an ultrafiche is selected.